The present invention relates to a forming machine comprising at least one forming station having a punch and a die as tools and a device for setting the axial position of one of the two tools.
After the initial fitting or the exchange of the tools, i.e. of the punch and/or the die, in a forming station, it is often necessary to still accurately set their position so that the workpieces are exactly formed in the desired manner during the operation of the forming machine. In particular, the axial mutual position of the punch and the die must be correct during the forming, which can be achieved by setting the axial position of at least one of the two tools. Since the tools are subjected to high impact forces during the forming, the device for setting the axial position must be of accordingly robust design.
Setting devices which comprise a vertically displaceable adjusting wedge have therefore often been used up to now. A forming machine having such a setting device for each forming station is described, for example, in U.S. Pat. No. 4,898,017. The adjusting wedge, which in each case is displaceable in the vertical direction by means of a setting screw, bears with a bearing surface against a pressure plate, which is fastened to a slide via a further plate. The punch belonging to the forming station is supported via a plurality of intermediate elements on the other side of the adjusting wedge, this other side forming an inclined plane. The axial position of the punch is adjusted by vertical displacement of the adjusting wedge on account of the inclined plane of the latter.
However, a problem with such setting devices is that impression recesses produced in the pressure plate by the adjusting wedge may occur due to the high impact forces during the forming, these impression recesses, on the one hand, impairing an adjustment of the adjusting wedge and, on the other hand, encouraging the generation of bending fractures if the adjusting wedge comes to lie above an edge of an impression recess after a displacement. In addition, the introduction of force to the pressure plate and ultimately to the slide changes during a displacement of the adjusting wedge.
In view of the disadvantages of the hitherto known setting devices, described above, in forming machines, the object of the invention is as follows. A forming machine of the type mentioned at the beginning comprising at least one forming station having a punch and a die as tools and a device for setting the axial position of one of the two tools, in which forming machine the introduction of force to a parent body does not change substantially during an adjustment of the adjusting wedge, is to be provided. Here, the expression parent body refers in particular to the machine body, the machine body with pressure plate, the press slide, or the press slide with pressure plate. In addition, the risk of a fracture of the adjusting wedge is preferably to be avoided. Impression recesses which cannot be avoided are not to impair the adjustment of the adjusting wedge.
This object is achieved by the forming machine according to the invention.
The forming machine according to the invention comprises at least one forming station having a punch and a die as tools and a device for setting the axial position of one of the two tools, the device comprising an adjusting wedge having a bearing surface which bears against a parent body. The essence of the invention, then, consists in the fact that the adjusting wedge is a rotary wedge disk which is rotatable about a rotation axis and which has the bearing surface on one disk side and an inclined plane on the other disk side, and the device also comprises a pressure piece having an end face which bears against the inclined plane in such a way that it is displaced relative to the rotary wedge disk eccentrically to the rotation axis when the rotary wedge disk is rotated, the axial distance between pressure piece and parent body changing in the process.
Since the adjusting wedge is a rotary wedge disk which rotates during an adjustment, the bearing surface also rotates on the parent body and is not displaced longitudinally. As a result, the introduction of force to the parent body is not changed substantially during an adjustment of the adjusting wedge and is therefore more favorable than in the previous forming machines.
The bearing surface is preferably circular and rotates on the spot on the parent body when the rotary wedge disk is rotated. This means that the rotary wedge disk rotates in the impression recess possibly produced during the forming and never comes to lie above an edge of the impression recess. In this way, the risk of a fracture and the impairment of the adjustment of the adjusting wedge by impression recesses can be avoided or at least markedly reduced.
There is advantageously arranged on the rotary wedge disk a toothed rim, via which said rotary wedge disk can be rotated. On account of the drive of the rotary wedge disk via a toothed rim at the periphery, the bearing surface and the inclined plane are not impaired by drive elements.
There are preferably means for arresting the rotary wedge disk in each adjustable position. This can prevent unintentional rotation of the rotary wedge disk from being caused by the high impact forces occurring during the forming.
The angle of inclination of the inclined plane relative to the bearing surface is advantageously 10xc2x0 at most. The angle of inclination is thus smaller than the limit angle for self-locking, as a result of which unintentional displacement of the end face on the inclined plane can be prevented.
The pressure piece preferably comprises a rotatable part having the end face and a rotationally fixed pressure part connected thereto via first sliding surfaces. During the adjustment of the rotary wedge disk, the rotary part with the end face can then be rotated at the same time, whereas the pressure part is only axially displaced, as a result of which the adjacent tool does not rotate.
In an advantageous embodiment variant, the first sliding surfaces have the form of a convex spherical-surface section and, respectively, a concave spherical-surface section complementary thereto. This has the advantage that it is not absolutely necessary for the rotary part to be rotated relative to the rotary wedge disk during an adjustment of the latter.
In an alternative exemplary embodiment, the rotary part comprises an end-face part having the end face and an articulation part connected thereto via second sliding surfaces and having one of the first sliding surfaces. The second sliding surfaces preferably have the form of a convex cylinder-envelope or spherical-surface section and, respectively, a concave cylinder-envelope or spherical-surface section complementary thereto. If the second sliding surfaces have the form of spherical-surface sections, it is not absolutely necessary for the rotary part to be rotated relative to the rotary wedge disk during an adjustment of the latter.
The forming machine according to the invention advantageously has means for rotating the rotary part or, if present, the articulation part coupled to the rotary wedge disk, these means preferably comprising a toothed rim which is arranged on the rotary part or, if present, on the articulation part. This ensures that the rotary part or the articulation part rotates together with the rotary wedge disk, as a result of which it can be ensured that the pressure piece does not tilt or that correct bearing of its end face against the inclined plane of the rotary wedge disk is maintained.
In an advantageous embodiment variant, the pressure piece and the rotary wedge disk have a through-hole and/or a curved through-slot for an ejector. There is preferably a central through-hole in the pressure piece or in part of the pressure piece, for example, if present, in the pressure part and possibly in the articulation part, and there is preferably a curved through-slot or a through-hole enlarged relative to the diameter of the ejector in the rotary wedge disk and the possible other parts of the pressure piece, so that an adjustment of the rotary wedge disk is possible despite the ejector.